The present invention relates generally to a zipper, and more particularly to a woven zipper. Specifically, the invention relates to a method of making such a zipper, and to an apparatus for carrying out the method.
A woven zipper is disclosed in U.S. Pat. No. 3,692,068 wherein a zipper tape is formed, into a longitudinally extending marginal portion of which a filament forming the coupling portions of the zipper is inserted by means of a weft inserting needle into a separately provided weft shed of threads, and is then woven between these additional threads and the basic tape. As compared to other types of zippers, this has the advantage that the filament is secured to the tape with a plurality of threads, and that the manner in which these threads are inserted is relatively simple because they always extend above the legs of each loop into which the filament is formed, and because they always extend beneath individual weft threads. Moreover, such a zipper can be produced continuously and can utilize a filament of any desired length, so that no interruptions in the manufacture result from running out of the thread supply or the filament supply.
German Pat. Nos. 2,023,055 and 2,125,470 disclose how a woven zipper can be made by, in effect, weaving a coil-forming filament onto the zipper tape as the latter is being produced. The filament is connected to the tape by the weft threads which engage those loop portions of the coil convolutions that overlie the tape. While this approach to zipper making has many advantages, it does have the drawback that the filament coil is not very sturdily secured to the tape. Also, the position of the individual coil loops are not as finely fixed as is desirable and, because of the engagement of the aforementioned loop portions by the weft threads, these loop portions are not available to guide the zipper slider, as would be desirable in the interest of easier operation of the latter.